Embodiments of the present invention relate to a liquid crystal display array substrate (LCD) and a manufacturing method thereof.
Thin film transistor liquid crystal displays (TFT-LCDs) possess advantages of small volume, low power consumption, low radiation, etc., and are gradually prevailing in the market of flat plate displays. As for a TFT-LCD, an array substrate and the manufacturing method thereof control, to a large extent, the performance, yield, and price of the final products. In order to efficiently reduce the production cost of TFT-LCDs and improve yield, the manufacturing process of a TFT-LCD array substrate is gradually simplified. Such manufacturing processes have been evolving from initial 7-mask processes to current 4-mask processes for example based on slit photolithography technology. Besides, 3-mask processes are under research and development.
One 3-mask process has been proposed in Chinese patent application CN 200510132423.X, in which a gate line and a gate electrode are formed through a patterning process with a first normal mask; a data line, a source electrode, a drain electrode, and a thin film transistor (TFT) channel region are then formed through a patterning process with a second gray tone mask; and a pixel electrode is finally formed through a patterning process with a third normal mask. In the third patterning process of this method, a transparent conductive film is directly formed on the surface of the photoresist for patterning by sputtering, and then the transparent pixel electrode is formed with directly contacting with the surface of the drain electrode by lifting off. In practice, the photoresist is prone to be modified during the sputtering process, thus the pixel region can be polluted and formation of the transparent conductive film by sputtering can fail. Furthermore, the pixel electrode performance is very important to the whole TFT-LCD array substrate and has a great influence on the display quality. Therefore, it is needed that the 3-mask process is improved so as to avoid the problems mentioned above.